diff --git a/native/ios/Comm.xcodeproj/project.pbxproj b/native/ios/Comm.xcodeproj/project.pbxproj
--- a/native/ios/Comm.xcodeproj/project.pbxproj
+++ b/native/ios/Comm.xcodeproj/project.pbxproj
@@ -46,6 +46,8 @@
 		B7BEE749279B3FB6009CCA35 /* GRPCStreamHostObject.cpp in Sources */ = {isa = PBXBuildFile; fileRef = B7BEE744279B3E20009CCA35 /* GRPCStreamHostObject.cpp */; };
 		CB1648AD27CFBBBB00394D9D /* ClientGetReadReactor.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 2DDA00CA889DFF0ECB7E338D /* ClientGetReadReactor.cpp */; };
 		CB1648AF27CFBE6A00394D9D /* CryptoModule.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 71BF5B7B26BBDA6100EDE27D /* CryptoModule.cpp */; };
+		CB38B48228771C7A00171182 /* NonBlockingLock.mm in Sources */ = {isa = PBXBuildFile; fileRef = CB38B47B287718A200171182 /* NonBlockingLock.mm */; };
+		CB38B48328771C8300171182 /* NonBlockingLock.mm in Sources */ = {isa = PBXBuildFile; fileRef = CB38B47B287718A200171182 /* NonBlockingLock.mm */; };
 		CB38F2B1286C6C870010535C /* MessageOperationsUtilities.cpp in Sources */ = {isa = PBXBuildFile; fileRef = CB38F2AF286C6C870010535C /* MessageOperationsUtilities.cpp */; };
 		CB38F2C0286C6CDF0010535C /* MessageOperationsUtilities.cpp in Sources */ = {isa = PBXBuildFile; fileRef = CB38F2AF286C6C870010535C /* MessageOperationsUtilities.cpp */; };
 		CB3C621127CE4A320054F24C /* Logger.mm in Sources */ = {isa = PBXBuildFile; fileRef = 71CA4A63262DA8E500835C89 /* Logger.mm */; };
@@ -189,6 +191,7 @@
 		CB1648B027CFD07E00394D9D /* CommRelease.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; name = CommRelease.entitlements; path = Comm/CommRelease.entitlements; sourceTree = "<group>"; };
 		CB30C12327D0ACF700FBE8DE /* NotificationService.entitlements */ = {isa = PBXFileReference; lastKnownFileType = text.plist.entitlements; path = NotificationService.entitlements; sourceTree = "<group>"; };
 		CB38B4792877179A00171182 /* NonBlockingLock.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = NonBlockingLock.h; path = Comm/TemporaryMessageStorage/NonBlockingLock.h; sourceTree = "<group>"; };
+		CB38B47B287718A200171182 /* NonBlockingLock.mm */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.objcpp; name = NonBlockingLock.mm; path = Comm/TemporaryMessageStorage/NonBlockingLock.mm; sourceTree = "<group>"; };
 		CB38F2AE286C6C870010535C /* MessageSpecs.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = MessageSpecs.h; path = PersistentStorageUtilities/MessageOperationsUtilities/MessageSpecs.h; sourceTree = "<group>"; };
 		CB38F2AF286C6C870010535C /* MessageOperationsUtilities.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = MessageOperationsUtilities.cpp; path = PersistentStorageUtilities/MessageOperationsUtilities/MessageOperationsUtilities.cpp; sourceTree = "<group>"; };
 		CB38F2B0286C6C870010535C /* MessageOperationsUtilities.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = MessageOperationsUtilities.h; path = PersistentStorageUtilities/MessageOperationsUtilities/MessageOperationsUtilities.h; sourceTree = "<group>"; };
@@ -519,6 +522,7 @@
 		CB38B4782877177B00171182 /* TemporaryMessageStorage */ = {
 			isa = PBXGroup;
 			children = (
+				CB38B47B287718A200171182 /* NonBlockingLock.mm */,
 				CB38B4792877179A00171182 /* NonBlockingLock.h */,
 			);
 			name = TemporaryMessageStorage;
@@ -918,6 +922,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				CB38B48228771C7A00171182 /* NonBlockingLock.mm in Sources */,
 				71009A7826FDCA67002C8453 /* tunnelbroker.grpc.pb.cc in Sources */,
 				B7BEE749279B3FB6009CCA35 /* GRPCStreamHostObject.cpp in Sources */,
 				718DE99E2653D41C00365824 /* WorkerThread.cpp in Sources */,
@@ -957,6 +962,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				CB38B48328771C8300171182 /* NonBlockingLock.mm in Sources */,
 				CB38F2C0286C6CDF0010535C /* MessageOperationsUtilities.cpp in Sources */,
 				CB1648AF27CFBE6A00394D9D /* CryptoModule.cpp in Sources */,
 				CB1648AD27CFBBBB00394D9D /* ClientGetReadReactor.cpp in Sources */,
diff --git a/native/ios/Comm/TemporaryMessageStorage/NonBlockingLock.mm b/native/ios/Comm/TemporaryMessageStorage/NonBlockingLock.mm
new file mode 100644
--- /dev/null
+++ b/native/ios/Comm/TemporaryMessageStorage/NonBlockingLock.mm
@@ -0,0 +1,78 @@
+#import "NonBlockingLock.h"
+#import <string>
+
+@implementation NonBlockingLock
+- (instancetype)initWithName:(NSString *)lockName {
+  self = [super init];
+  if (self) {
+    _lockName = [lockName cStringUsingEncoding:NSUTF8StringEncoding];
+    _lockHandle = nil;
+  }
+  return self;
+}
+
+- (BOOL)tryAcquireLock:(NSError **)err {
+  if (_lockHandle) {
+    *err = [NSError errorWithDomain:@"app.comm"
+                               code:EBUSY
+                           userInfo:@{
+                             NSLocalizedDescriptionKey :
+                                 @"Attempt to acquire already held lock."
+                           }];
+    return NO;
+  }
+  sem_t *lock = sem_open(self.lockName, O_CREAT, 0644, 1);
+  if (lock == SEM_FAILED) {
+    *err = [NSError errorWithDomain:@"app.comm"
+                               code:errno
+                           userInfo:@{
+                             NSLocalizedDescriptionKey : [NSString
+                                 stringWithCString:strerror(errno)
+                                          encoding:NSUTF8StringEncoding]
+                           }];
+    sem_close(lock);
+    return NO;
+  }
+  if (sem_trywait(lock)) {
+    *err = [NSError errorWithDomain:@"app.comm"
+                               code:errno
+                           userInfo:@{
+                             NSLocalizedDescriptionKey : [NSString
+                                 stringWithCString:strerror(errno)
+                                          encoding:NSUTF8StringEncoding]
+                           }];
+    sem_close(lock);
+    return NO;
+  }
+  _lockHandle = lock;
+  return YES;
+}
+
+- (void)releaseLock:(NSError **)err {
+  if (!self.lockHandle) {
+    *err =
+        [NSError errorWithDomain:@"app.comm"
+                            code:ENODATA
+                        userInfo:@{
+                          NSLocalizedDescriptionKey :
+                              @"Attempt to release lock that was not acquired."
+                        }];
+    return;
+  }
+  sem_post(_lockHandle);
+  sem_close(_lockHandle);
+  _lockHandle = nil;
+}
+
+- (void)destroyLock:(NSError **)err {
+  if (sem_unlink(_lockName)) {
+    *err = [NSError errorWithDomain:@"app.comm"
+                               code:errno
+                           userInfo:@{
+                             NSLocalizedDescriptionKey : [NSString
+                                 stringWithCString:strerror(errno)
+                                          encoding:NSUTF8StringEncoding]
+                           }];
+  };
+}
+@end